It's A Long Story
by sleepyxcoffee
Summary: FORMERLY TITLED SIN. Really, this was all Clary's fault. If it weren't for her, Jace and Clary wouldn't be more than a century in the past with their ancestors. Now, they're stuck here, and they need to find a way back. Takes place during the time Tessa arrives at the Institute in CA. CoG AU. Now a multi-chap.
1. Chapter 1

**AN: My first fic for TMI! Short, fluffy and not-so-sweet. Takes place in CoG, after they meet Ithuriel. Clary managed to draw a portal, but it was sorta messed up and landed them in the London Institute more than a century in the past. Guest appearance from TID charries at the end. Um, well, I really don't know why I listed humor as one of the genres, but it has something to do with the little scene with the TID characters at the end.**

Really, Clary was to blame for all of this.

If Clary had not insisted on going to Idris, he wouldn't have ended up (alone) with her more than a century in the past. If Clary had been slightly more careful drawing that rune to get out of the manor (not that he wasn't grateful they weren't currently crushed), they wouldn't be here. Clary was the one seducing him, the one making him fall in love with her. Clary's rune had landed them here. And it was Clary's fault for being so damn cute, for being so pretty and _lovable_.

It was Clary's fault. All of it.

Honestly, Jace couldn't remember what this particular argument was about. Ever since the Valentine Incident (which was something he _never _spoke of), Jace had spent all his time arguing with Clary instead of talking with her. It was sort of a way to keep himself from kissing her and causing a hellishly awkward situation.

Usually, that plan worked. But the keyword rested on usually - meaning, every now and then, it went downhill. Today was one of those days - Jace shell-shocked from discovering he was part-demon, Clary shell-shocked from seeing an angel, with neither of them really thinking clearly.

"You're my sister, Clary!" Jace shouted. Usually, this was where most arguments ended up. Taking a turn and walking down the brother-sister path. Clary's mouth was agape. "Is that what this is all about?" she asked, her voice high. "Brothers aren't supposed to feel like this with their sisters!" Jace hissed. But that was human brothers… maybe with demons, it was normal and okay to fall in love with your siblings.

Clary's green eyes - oh, her beautiful green eyes - widened. "You said you'd be my brother from now on." Her tone was accusing. "Maybe I was lying," Jace answered, beginning to pace. "Jonathan Christopher Morgenstern -" Clary began, but she was interrupted by Jace spinning on his heel and glaring at her.

"Don't. Call. Me. That." His voice was low, angry and hissing like a snake. He really didn't need a reminder of the fact that he was Valentine's son - and, by default, Clary's brother. Something resembling fear flickered in Clary's eyes. Immediately, Jace regretted his words. He sighed. "Look, Clare -" he began, but he was cut off.

"So do you want to my brother or not?" Her words were sudden, confusing, and seemingly pointless. Jace narrowed his eyes and took a few steps closer towards her, to the point there was barely any space between them.

"You're my sister, Clary," he hissed. But, oh, her scent was so intoxicating, and Jace really couldn't help himself, and if that scene with Ithuriel really meant anything, then it meant Jace was part-demon, and demons could be evil and otherworldly and had no moral compass and were _like this_...

His lips crashed onto hers, and everything went spiralling out of control. Jace felt, more than heard, Clary's gasp of surprise, before she returned the kiss, deepening it and tangling her fingers in his hair.

Jace gripped her waist and pushed her against the nearest wall, pinning her. She was _everywhere_, her hands running over his chest, his waist, fingers slipping through his belt loop and pulling him closer (which, really, was impossible, seeing how close they were already)...

Clary swung one leg over his hip. Jace, more than happy to help, lift her up by the hips so she could swing the other leg. She was a bit higher up this way, and Jace didn't have to lean down so much to kiss her. Her hands slipped up his shirt, and he slipped _his _hands up her shirt, tracing her spine and running them lightly over her bra, while she traced the lines and curves of his back. Clary let out a groan, and he responded with one of his own.

He really wasn't sure what would have happened next. Most likely they would have gone even farther - and it was for that reason he was grateful for the sound of someone clearing their throat.

Immediately, the duo leapt apart. Clary fell rather ungracefully to the ground, and Jace stumbled over an ill-placed carpet behind him (but a carpet really can't be ill-placed, can it?).

A young man their age with black hair and blue eyes, like Alec, but at the same time nothing like Alec, stood nearby, eyebrow raised. The girl who had led them here - Tessa, her name was - stared at them. "I thought you said they were siblings?" the boy next to her, odd with his silver hair and silver eyes, whispered. His eyes were as large as saucers, and his jaw looked like it was about to hit the floor.

Tessa stared at them, mouth open and eyes wide. "That's what they said."


	2. Chapter 2

**AN: Wow! I didn't expect such positive response! Thanks to you guys, I'm continuing this old thing. Another one-shot for you! Well, this is more like a series now. I'm planning to finish this arc - probably around five chapters or so. Little secret - this is my first multichaptered story. How is it so far? And, um, I sort of need a beta. My usual beta is officially off FFnet, and she doesn't read TMI and TID anyway.**

**Anyway, now that the TID characters are main characters, should I move this to crossovers? Or keep it here?**

"Who are you?" Charlotte asked, for what felt like the thousandth time. "I'm Clary Fray." Charlotte sighed. She had been getting the same answer repeatedly, with not the slightest variation. "And who are your parents?" she asked. "Jocelyn Fray."

Questioning Jace had resulted in even more bizarre results. "I'm Jace," he answered to Charlotte's questions. When she had asked him who his parents were, Jace had become silent, and Clary had filled it, saying, "It's complicated."

In other words, Charlotte's investigation was getting her nowhere. "Tessa tells me you and Clary are siblings." Charlotte left out the part where Tessa mentioned finding them making out in the kitchen. Both Jace and Clary had looked immensely annoyed at that. "So you would be Jace Fray, am I correct?"

"No!" both of the mysterious people shouted at once. "I'm Clary Fray. He's Jace." Charlotte leaned back in her seat. She didn't even know how that was possible. "No surname?" she asked. "It's complicated," Jace repeated. Charlotte decided to switch tactics.

"Are you sure you're siblings?" If possible, Jace and Clary looked even more uncomfortable. "Um…" Clary's voice trailed off. "Oh, we're siblings alright," Jace muttered darkly, the look in his eyes murderous. Charlotte somehow got the feeling both siblings wished it wasn't true.

"Tell me something about yourselves," Charlotte demanded. If she couldn't figure out who these people were, she could at least get to know them. "We're from New York," Clary pitched in helpfully. "Why are you dressed so odd?" Charlotte asked Clary. Clary and Jace exchanged a look.

"These are normal New York clothes," Clary insisted. Charlotte couldn't help but think Clary was dressed rather like a man, with her stiff dark blue pants and loose black T-shirt. As for Jace - well, he was dressed in typical Shadowhunter gear. "The question would be why _you're _dressed so odd," Jace put in innocently. Charlotte glared at him.

She glanced at the clock on her desk. The three of them were in Charlotte's office, Charlotte sitting behind her desk and the two mysterious visitors sitting in front of her. It was already six PM. "Do you want to eat?" Charlotte asked. These visitors may be frustrating, but Charlotte didn't exactly want to starve them to death.

"Sure," Jace answered.

xXxXxXxXxXxXxXxXx

"Who _is _that girl?" Jessamine demanded as Sophie laced her dress. "I don't know, miss," Sophie admitted. Jessamine had been forced to lend Clary one of her smaller dresses, seeing as Tessa's clothes were too large to fit the tiny girl.

"She's dressed like a boy!" Jessamine scoffed. Sophie continued lacing the corset quietly. "Tighter, Sophie," Jessamine ordered. The maidservant did as she was told, tightening the corset she was lacing around Jessamine. "That's enough," Jessamine declared. "Now go check on Tessa and that redhead. Make sure they haven't destroyed anything."

Obediently, Sophie slipped out of Jessamine's room, going to Tessa's. She knocked on the heavy wooden door. "Come in!" Tessa called. Sophie opened it and walked into the girl's room. Tessa and Clary were standing in front of a mirror. Clary looked very uncomfortable, while Tessa looked sympathetic.

"These clothes are so tight," Clary commented. "How can you stand them?" Tessa laughed. "They're fine once you get used to it," she assured. "Sophie, give us a hand and tie Clary's clothes." Feeling slightly bad, Sophie did as she was told. Clary winced.

"Izzy would love it here," she sighed. "Who?" Tessa asked. "My friend, Isabelle," Clary explained. "She loves pretty clothes." Tessa's brow furrowed. "A bit like Jessamine, if you asked me." Clary's eyes widened. "Isabelle is nothing like Jessamine," she exclaimed. "Izzy - she loves to fight. She has whips, and she knows how to use them."

A girl who liked to fight? That was new, Sophie thought. "Charlotte tells me you come from New York," Tessa said. Clary started. Whether it was from Tessa's words or the tight corset, Sophie wasn't sure. "Brooklyn, actually," Clary admitted.

"What is this?" Tessa asked, lifting a black rectangular device from Clary's things scattered on Tessa's table. "Oh, that's my phone," Clary dismissed. "And this?" Tessa picked up another black rectangular device. "That's a Sensor."

Tessa looked surprised. "Henry - he's making one of these," she told Clary. "So they're already finished where you come from?" Clary looked uncomfortable. "Yeah," she answered. "Finished, miss," Sophie declared, stepping away from Clary. She looked even more uncomfortable in the stiff clothes. "Thanks, Sophie," she gasped.

The redhead frowned. "And please," she added, "it's just Clary. No miss." Surprise streamed through Sophie. "Sophie, be an angel and help me with my clothes. No offense, Clary, but you're terrible at lacing dresses." Clary looked somewhat sheepish. "No offense taken, Tess."

"So - Jace, he's your brother, right?" Tessa asked. If possible, Clary's discomfort seemed to increase. "Sort of," she admitted. "I mean, we just found out a couple of months ago." Tessa's eyebrow quirked upwards. "How's that possible?" Clary shifted slightly. "It's just… well…"

Sophie sensed this subject going down a dangerous path. "I think we'd better be going, miss, Clary. Miss Charlotte told us to be down at seven." Clary and Tessa both nodded. "Thank you, Sophie."

The moment Sophie stepped out of the room, Tessa turned to face Clary. "Sorry," she apologized awkwardly. Clary smiled tightly. "It's fine," she assured the other girl.

The two girls made their way downstairs to the dining hall. When they arrived, everyone but Henry were already seated. Tessa made a beeline for the seat between a boy with silver hair and a boy that looked like an eccentric combination between Jace and Alec. Clary figured Henry would sit next to Charlotte, leaving the only empty seat between Jace and Jessamine.

Feeling a bit more than awkward, she slipped into the empty chair. "Hi," she whispered to Jace. Jace smiled tightly at her. He looked out-of-place in Will's clothes. "How are we getting home?" Clary asked. Jace shrugged. "Alec mentioned that Magnus may have briefly lived in London," he muttered out of the corner of his mouth.

"You think he'd help us?" Jace shrugged again. "Don't know." Clary shifted slightly as Sophie and Agatha arrived with their food. "Thanks," the redhead thanked the maid and cook. They both smiled at her as they continued serving the rest of the table. At that moment, Henry walked in and took a seat besides Charlotte. She smiled at him. "So, this is the London Institute?" Jace asked.

Charlotte nodded. "We can arrange for a ship back to New York," she offered, "but the Enclave… well, they'd want to know about you two being here." Both Tessa and Will shot up in their seats, and Jem stiffened. "Did you tell them?" they asked. Charlotte looked uncomfortable.

"You did!" Will accused. "I had to!" Charlotte protested. She looked apologetic. Will sighed. "Great, now we can expect the Enclave to come knocking at any given time," he muttered darkly. Pointing accusingly at the two newcomers, he asked, "Where did they even come from?"

Jace and Clary exchanged a look. "We're from New York," Clary repeated. Some how, she didn't think blurting out the fact that they had accidentally time traveled more than a century in the past was a good idea.

"You randomly showed up on our front door with no explanation!" Will exclaimed. "It's complicated," Jace argued. "_Everything _is complicated with you two!" Will shot back. "You didn't even give us a surname!" Clary bit her lip. She sensed a fight coming on.

"Oh, is that what this is all about? The fact that I didn't give you my surname?" the blond shouted at Will. "Stop!" Jace ignored her as Jem and Tessa both tried to restrain Will. "Jace, stop it. Don't get in a fight with them," Clary whispered to her brother (oh, it was terrible to think of him like that). She tugged at his sleeve fruitlessly. Fortunately, Jace and Will seemed to be content with just glaring at each other.

Clary sighed and slid down her seat. "We didn't give you his surname because it's confusing," Clary explained. "But if you really need one, it's Wayland." Charlotte frowned. "And how is that possible?" she asked. "It's complicated," Jace answered.

"That seems to be your answer for everything," Jessamine muttered under her breath. "That's because it _is _the answer to everything," Jace shot back. "Now, does anyone know where Magnus Bane is?" The Institute residents looked surprised.

Jem was the first to speak. "Why do you need Magnus Bane?" he asked. Clary shot Jace a glare. Now it would be hard to explain. "It's a long story," she began. Henry leaned forward, attentive for the first time since dinner started.

"We have time."


	3. Chapter 3

**AN: MASSIVE AN AHEAD! Thank you so much for your amazing reviews! Shout out to ifyouknew and RitzaHerondale. Thanks so much to LondonGirl for your amazing review. I'm planning to slow everything down a bit and plunge into details, once I've sketched out the plot. LondonGirl, do you have an account? I'd love to personally reply to your review.**

**As for to all the followers and favoriters, I swear I usually send a thank you PM for follows and favorites, but I've been sort of drowning from exams lately. I'll get around to thanking everyone later (hopefully). And you may have noticed I changed the title and category - I found that the current ones fit much bettter.**

**And I still need a beta! Preferably someone who's been on for at least a year, familiar with both TMI and TID, loves to give reviews and concrit. I'm also willing to beta that person's stories, since I love betaing. And, oh, I'm considering writing another fanfic. A Shadowhunters-in-high school story. I'll post the summary with the next chapter.**

It was decided by Jace that Clary would do the explaining, seeing as it was her fault they were there anyway. "I wasn't the one who decided to have a chat with an angel," she shot at him, leading to looks of confusion from the Londoners.

"You talked with an _angel_?" Charlotte asked in disbelief. She looked confused. "It's-" Jace began, but Will cut him off. "Don't you dare say it's complicated. Don't you _dare_." Jace shot him an annoyed glare.

"Actually, I was going to say it's a long story. Nice to know you find me interesting enough to try predicting my speech patterns, though." Tessa choked on her tea, while Will glared back at Jace.

Charlotte cut him off before he could speak. "Explain," she ordered Jace sternly. Jace frowned. "Hey, it's not my fault we're here. That goes to Clary." Clary shrunk in her seat. "It was an accident!" she protested.

Jem frowned. "Exactly what was an accident?" he asked. Clary muttered something under her breath, pale cheeks flaming. "You'll have to speak up," Charlotte told her gently. "I... accidentally portaled us here?" she offered weakly. Jem's brow furrowed. "How do you accidentally portal anyone?" he questioned.

Clary ducked her head sheepishly. "There was a manor falling on us. I meant to portal us only a few miles southeast," she defended. "Except… well, I may have misjudged the distance and we ended up on a different continent. And, um…" Her voice trailed off. Jace rolled his golden eyes. "What she means to say is that she somehow found a gap in the time-space continuum, and wrenched us out of our own time, and now, according to the calendar, we're more than a century in the past."

Jaws gaped at them from around the table. "Let me get this straight," Tessa began slowly. "You accidentally portaled Jace and yourself a century in the past - to a different continent, no less?" Clary looked sheepish.

"...yes?" Henry shot up in his seat. "That's amazing! What rune did you use? How did it work? If we could channel that magic into a device, then-" Charlotte cut him off. "I'm sorry, dear, but the important matter at hand is the fact that we've got two time-travellers at hand." She frowned at the two from the future. "Actually, I didn't know time-travelling was even possible.

Jace laughed darkly. "All stories are true," he pointed out. "Mummies don't exist," Clary pointed out. Jem's brow furrowed. "Are you sure? I think I saw some mummies a few weeks ago at a party." Will's eyebrow shot up. "Whoa, seriously?" he asked.

Charlotte cleared her throat. "We're straying off subject," she reminded. "Now, how are we going to get these two back?" Jace smiled at her - a dark, morbid smile.

"Magnus Bane, remember?"

xXxXxXxXxXxXx

"I thought," Clary said, "that Magnus Bane was the High Warlock of Brooklyn." Jace shrugged. "More like the High Warlock of New York. He's all over the place." Jace frowned thoughtfully. "But then again, High Warlock of Brooklyn does have a nice ring to it." Will looked curious.

"So Magnus moves to Brooklyn?" he asked. Clary nodded. "Yeah." The three of them were standing in front of Magnus's door. Jace took a deep breath. "Well, here goes nothing." He knocked sharply on the door. It swung open. "Who are you?" Magnus asked, sounding slightly bored. Clary couldn't help but stare at Magnus. He looked less… Magnus. Not as hippy-like, with a few less sparkles.

Apparently, Magnus realized Clary was staring at him. "Why the stare?" the tan man questioned. "I…" Clary's voice trailed off. "We need your help," Will cut in briskly. "These two - well, they're time travellers from New York."

To say Magnus looked shocked would be an understatement. It would be more accurate to say that looked like an elephant-lion hybrid had romped into his house, eaten all his furniture then destroyed the London Bridge. Actually, he looked more surprised than that, Clary thought.

"_Time travellers?"_ Magnus's voice was weak. "That's impossible." Magnus stood a bit to the side, holding the door open wider. "Come in, and we'll talk." The three Shadowhunters walked into Magnus's house. "Careful," he added, "don't get Camille's carpet dirty." Clary frowned. "Camille?" she asked. "Magnus's girlfriend," Will clarified.

Clary cocked her head to the side in confusion. "Magnus has a girlfriend?" she asked. Magnus sighed. "You're really behind on news, aren't you?" A flush spread over Clary's cheeks. "I come from a hundred thirty years in the future," she defended. Jace overtook her with a few long strides. Sighing, Clary took her phone from her pocket. She waved it around hopefully. No reception. She should've known - Clary doubted cellphone satellites even existed at this time.

Will gave her phone a look of interest. "What's that?" he asked. "It's a phone," she explained. Will looked impressed. "A portable one?" Clary nodded. "Nice," he commented approvingly as they followed Jace and Magnus into a living room.

Clary had to admit the room was nice. There was a sort of elegant grace to it. Magnus gestured at the empty sofa. "Take a seat," he ordered them. The three Shadowhunters did just that - Jace somehow ending up between Will and Clary.

Magnus settled himself into an armchair across them. "So," he began, "exactly what happened?" Clary repeated the story about Ithuriel, the mansion and the portal. She left out the part where they found out Jace had demon blood, and that Valentine had injected innocent babies with blood.

The warlock whistled when Clary finished the tale. Jace had gotten up and was examining items on shelves and tables. He picked up a tooth, flipping it between his hands. "Careful," Magnus warned, "that thing is poisonous." Not missing a beat, Jace slammed it back onto the table.

"So you want me to send you back into the future?" Magnus asked. Clary nodded. "More or less." Magnus frowned. "That's hard," he stated. Clary nodded again. "If I show you the rune I used, would you be able to… well, adjust it? Edit it? Turn it into a rune that can do what we want it to?"

Magnus frowned. "No one can create new runes," he warned. "Clary can," Jace piped up. Both Magnus and Will stared at Clary. "How?" Will demanded. "It's-" Will's eyes narrowed. "Don't you dare say it's complicated."

Clary's lips curved into a small smile. "It is complicated," she admitted. "But, well, long story short, my mother was fed angel blood by my father when she was pregnant." Magnus and Will stared at her, mouths hanging open. "That's…" Magnus groped for the right words. "Immoral? Insane? Evil?" Jace suggested. "Cause our dad is all of that."

"I was about to say terrible," Magnus offered lightly, "but those adjectives work fine as well." He turned to Clary. "I can try, but it won't be easy," he warned. "And I expect payment." Clary had been expecting this part. Magnus never did anything for free. "What do you want?" she asked.

Cat-like eyes stared at her. "Information," he decided at last. "I'm a warlock, Clary, and we're curious people. Tell me what the future's like, and I'll help you get home." Clary's brow furrowed. "But you're a warlock!" she exclaimed. "You're immortal. You'll see anyway."

A laugh escaped Magnus's lips. "I'm curious. Just a few facts you think I'll find interesting." Jace frowned slightly as he sat at a piano. "They say curiosity killed the cat." Magnus smiled, cat-eyes sparkling. "I'm not a cat, am I?"

Clary sighed. "Fine," she agreed. "Well, you put a block in my mind." Magnus looked confused. "Why would I do that?" he asked. "My mother asked you to. To protect me from the Shadow World," Clary explained. "Why would she want to protect you?" Will questioned.

"It's-" Will sighed. "It's complicated, it's a long story, I know." Magnus smiled grimly. "What else?" he asked. "You babysat Jace," Clary offered. Jace glared at her. "He did not babysit me, I was simply his houseguest while evading the Inquisitor," he argued. Magnus laughed.

"And…" Clary trailed off, thinking of facts that might interest the warlock. "You told my _parabatai _to call you," Jace offered helpfully. Clary choked. She had almost forgotten about that.

"How old is your _parabatai_?" Magnus asked curiously. "Eighteen," Jace answered. Will looked torn between amusement and disgust. "Let me get this straight - a seven-hundred-year-old warlock asked out an eighteen-year-old Shadowhunter?"

Clary frowned. "It sounds wrong when you put it that way," she grumbled. "And for the record," Jace added, "Magnus didn't exactly ask Alec out. Not yet, anyway." He grinned at Will's expression. Will stuck his tongue out at the golden boy.


End file.
